Battery Power Supply Device and Battery Power Supply System

The present application provides a battery power supply device and a battery power supply system. The battery power supply device includes a control module, a DC/DC conversion module and a battery. The DC/DC conversion module includes N DC/DC converters connected in series or in parallel. When the battery power is constant, more output current can be obtained when the N DC/DC converters are in parallel, and more output voltage can be obtained when the N DC/DC converters are in series. Embodiments enable a battery power supply device or system to meet voltage requirements of different loads and improve applicability of a battery.